314 BOTANICAL GAZETTE [ APRIL 
nical matter could be found in Oregon. Accordingly the author learned to 
set type, and for nearly eight years has “set up” form after form until the 800 
pages and more have been printed. We venture the assertion that no manual 
of botany, and probably no botanical work, has ever been issued at such a 
cost of labor to the author. 
The value of the book is just what the experience of the author has made 
it, and no one knows so well the plants of the region covered. In addition to 
this, Mr. Howell is to be congratulated upon his indomitable pluck, in the 
presence of which a few typographical errors here and there and a little lack” 
of typographical finish must be entirely forgotten.— J. M. C 
A study in heredity. 
A sTuDy in heredity by W. Johannsen’ reaches the conclusion that 
Galton’s law of regression is true in populations made up of several pure 
lines, but is not true in the pure lines taken singly. By a pure line is meant 
a group of individuals which have descended from a single self-fertilized 
individual. The author shows that a monomodal curve is not sufficient evi- 
dence that a population is homogeneous, but that a process of biological 
analysis must precede the general mathematical analysis, to attain satisfactory 
results. When Galton’s law is found to hold in self-fertilizing populations it 
is interpreted as the result of incomplete isolation of the pure lines, and when 
the isolation is complete, 2. e., in a single pure line, there is complete regres- 
sion of the mean characters of the offspring to the type of that line. This 
absolute fixity of type is too unique to be accepted without question, but if 
sustained by further research is a sufficiently important principle in questions 
of evolution in those special cases in which pure lines are involved, as in 
cleistogamous and other self-fertilizing —— andi in populations arising 
through parthenogenetic and vegetative reproduction. But exception may 
be taken to the author’s view that the principle is oe ue to all study of 
heredity. 
The results are based upon weight and form of seeds of Phaseolus vulgaris 
and on certain abnormalities in heads of rye. Only three generations are 
involved, and no account is taken of the influence of climatic fluctuations.— 
G. H. SHULL. | 
MINOR NOTICES. 
Tue Vermont Agricultural Experiment Station has issued a bulletin 
dealing with the flow of maple sap.’ The bulletin sets forth an enormous 
amount of experimental work, a large portion of which is directed to the 
physiological problems of sap pressure and sap flow. The effects of external 
7 JOHANNSEN, W., Ueber Erblichkeit in- Populationen und in reinen Linien. pp- 
68. fgs. 8. Jena: Gustav Fischer. 1903. 
*Jongs, C. G., Epson, A. W., and Morse. W. J., The mas sap flow. Bull. 
103, Vermont Agric. Expr. Sta. PP- 43-184. figs. 6. pls. 17. 1903 
